Hartley confident Celtic have bottle to bounce back
He said: "We've lost the last two games and people tend to go into crisis mode in that situation - but you lose matches, that's the nature of the business.
"But we'll bounce back, because we've got enough personality and character in the team.
"It was disappointing to lose on Saturday in the Old Firm game and again to Benfica. But we can actually take heart from parts of our performance in the match in Lisbon."